Means for making electrical connections



brlginal Filed Dec. 23, 1964 T \igg.

- 'K. M. 'HAMMELL ETAI- 3,474,394-

I MEANS FOR MAKING ELECTRICAL CONNECTIONS 3 Sheets-Sheet 1 ae U @2 F m Ian a! 40 30 I FTI Oct; 21, 1969 K-.M. HAMMELL ETAL 3 474 4 MEANS FORMAKING ELECTRICAL CONNECTIONS Zriginal med Dec. 23, 1964 s Sheets-Sheet:2

h INVENTORS (sMPee #42741 f/nnnsu.

BY Paeezr fknmtuu Camus Oct. 21, 1969 KM HAMMELL ET AL 3,474,394 MEANSFOR MAKING ELECTRICAL CONNECTIONS Original Filed Dec 23, 1964 5Sheets-Sheet 3 INVENTORS (EMPEQ IYmem #qpmeu eoaeer fEHA/LUN Camus/3,474,394 MEANS FDR MAKING ELECTRK'CAL CGNNECTIONS Kemper MartelHammell, Harrisburg, and Robert Franklin Cohaugh, Hershey, Pa.,assignors to AMP Incorporated, Harrisburg, Pa.

@riginal application Dec. 23, 1%4, Ser. No. 420,666, new Patent No.3,325,770, dated June 13, 1967. Divided and this application June 8,1967, Ser. No. 644,666 The portion of the term of the patent subsequentto June 13, 1984, has been disclaimed int. Cl. Hllr 33/ 88 US. Cl.339-176 6 Claims ABSTRACT 0F THE DISCLOSURE An electrical connectorconstitutes a dielectric housing and an electrical terminal providedwith a forked contact. The housing contains a passageway extendingtherethrough including an entrance through which a post enters and isdisposed therewithin. The passageway also includes section means forbearing on opposite sides of the post to stabilize the housing on thepost in one direction and the section means define centering means tocenter the forked contact for engagement on other opposite sides of thepost. Means are provided on the forked contact and in the passageway toguide the forked contact toward the section means and to maintain theforked contact in a predetermined position in the passageway.

CROSS-REFERENCE TO RELATED APPLICATION This application is a division ofUS. patent application Ser. No. 420,666, filed Dec. 23, 1964, now PatentNo. 3,325,770, issued June 13, 1967.

SPECIFICATION This invention relates to disengageable electricalconnectors for connecting conductors to terminal posts on a panelboard.

An object of the invention is to provide an improved electrical singleor multiple disconnect for connecting conductors to square orrectangular-sectioned terminal posts on a panelboard or mounting means.A further object is to provide a connecting device for connectingrelatively large conductors to relatively small terminal posts which aremounted on a panelboard. A still further object is to provide aconnector for connecting at least two external conductors to arelatively small terminal post where only a relatively short length ofthe post is available for making electrical connections with theexternal conductors. An additional object is to provide a housing ofdielectric material which is cooperable with a terminal post and withfork-type terminals in the housing so as to provide axial stability intwo planes and stability against rotation of the housing on the post. Astill further object is to provide a connecting device which isparticularly intended for usage where the spacing between terminal postsand terminal panels are limited.

These and other objects of the invention are achieved in a preferredembodiment comprising a housing having axial openings extending into thehousing from both ends. The lower end of the opening in the housingcomprises a square or rectangular post entrance portion, two oppositesides of which extend into a terminal-receiving portion in a manner suchthat these two opposite sides provide a constricted section bearing onan extended length of post. The widths of the post-bearing areas aresomewhat smaller than the width of the post so as not to interfere withmating of the terminal and the post. The widths of the post-bearingareas may be substantially nited States Patent 0 3,474,394 Patented Oct.21, 1969 "ice equal to the distance between the contact areas of theforked terminals so as to provide a centering guide for a terminalinserted into a housing prior to the housing 'being placed on a post.The post entrance portion has a cross-section equal to or slightlysmaller than the crosssection of the terminal post to provide africtional sliding fit when the housing is telescoped onto the post.This frictional fit stabilizes the housing rotationally and incooperation with the above-mentioned two opposite sides in at least oneplane axially. The contact-receiving portion is provided with guidesurfaces in the form of downwardly and centrally sloping guide planesleading into a lower centrally constricted section for each terminal.The constricted section for each terminal is provided by V- shaped ribsextending centrally downwardly from the upper opening. The dual functionof these ribs will be presented later. Cavities on each side of theconstriction extending downwardly from the upper end of the opening areprovided to obtain uniform wall sections throughout the molding toreduce curing time and to increase dimensional accuracy. The uppercontact-receiving portion is enlarged having a cross-section sufficientto admit the crimped insulation and wire portions of the elec tricalconductor which are to be connected to the post. The housing ispreferably used in conjunction with forktype spring contacts which arecrimped onto the ends of the conductors. In the case of relatively largeconductors, it is desirable that the thickness of the spring contact besubstantially greater than half the thickness of the mating post inorder to provide adequate wire retaining strength in the wire barrel ofthe contact and adequate contact force in the forked contact region.Thus, the provisions in the cavities of the housing provide operatingclearance for such contacts.

The spring contacts comprise a forked section having a slot extendingaxially inwardly from their ends; the width of this slot near the endsbetween the contact areas being substantially equal to one-half thethickness of the terminal post and the width of the slot near thejuncture of the tine being slightly larger than the post thickness sothat two or more such contacts can be moved axially onto the post instraddling relationship thereto, each providing substantial contactforce with its two contact surfaces against said post. The arrangementis such that the two fork-type terminals on the ends of the conductorscan be moved into the housing and into the terminal-receiving portionthereof so that they will straddle the post with the opposed edges ofthe slot at the contact area bearing against the exposed sides of thepost to establish the electrical connection.

Other objects and attainments of the present invention will becomeapparent to those skilled in the art upon a reading of the followingdetailed description when taken in conjunction with the drawings inwhich there are shown and described illustrative embodiments of theinvention; it is to be understood, however, that these embodiments arenot intended to be exhaustive nor limiting of the invention but aregiven for purposes of illustration and principles thereof and the mannerof applying them in practical use so that they may modify them invarious forms, each as may be best suited to the conditions of aparticular use.

In the drawings:

FIGURE 1 is a fragmentary perspective view showing a portion of apanelboard having terminal posts extending therefrom and having anelectrical connecting device in accordance with the invention mounted onone of the terminal posts;

FIGURE 2 is a cross-sectional view showing a connector housing inaccordance with the invention in alignment with the terminal post andwith a fork-type terminal which is to be connected to the terminal post;

FIGURE 3 is a view taken along lines 33 of FIG- URE 2;

FIGURE 4 is a view taken along lines 44 of FIG- URE 2;

FIGURE 5 is a view similar to FIGURE 2 but showing the connector housingmounted on the terminal post with the fork-type terminals sectioned atthe upper ends of their slots and disposed in the housing andelectrically connected to the post;

FIGURES 6 and 7 are views taken along lines 55 and 66 of FIGURE 4',

FIGURE 8 is a perspective view of a contact terminal on the end of aconductor of the type used for connecting the conductors to theterminal; and

FIGURE 9 shows an alternative embodiment of a connecting device inaccordance with the invention.

FIGURE 1 shows a portion of a panelboard 4 having a multiplicity ofterminal posts 2 mounted therein in accordance with a coordinate gridsystem. In the embodiment shown, the posts extend through board 4 to theopposite side thereof as shown at 2 so that individual modulescontaining circuit components may be mounted on the underside of board 4and the necessary electrical connections between the modules can be madeby means of projecting portions 2 of the posts by any suitable wiringmethod. In FIGURE 1, a relatively small conductor 8, which is matched tothe size of post 2, provides electrical connection between the terminalposts as shown by means of clip-type connections 6 which are describedmore fully in the copending application of Robert F. Cobaugh, Ser. No.171,074, filed Feb. 5, 1962, now US. Patent No. 3,239,918.Alternatively, connections may be provided between the posts in theregion adjacent to the panel by conductors similar to *8 by means ofwelded or wrap-type connections.

The disclosed embodiment of the present invention is particularlyintended for usage under circumstances where one or two furtherconductors 10, 12 are to be disengageably connected to a post 2 and/ orwhere size limitations as regards the post or the conductors renders theemployment of additional clip-type or wrap-type connections impractical.Thus, in FIGURE 1, it will be apparent that conductors 10, 12 may besubstantially larger than conductor 8 and could not conveniently beconnected to a terminal post by means of a clip-type, wraptype, or weldconnection. This does not preclude the advantageous use of smallerconductors 10, 12 being disengageably connected to small posts as thisis also contained within the invention. With small conductors only, thecrimpable wire and insulation supporting barrels of the forked terminalsare preferably proportional to the cross-section of Wire, the thicknessof the forked end of the terminal is preferably identical to those usedon larger conductors.

The disclosed embodiment of the invention comprises an insulatinghousing 14 into which fork-type contact terminals 16 (FIGURE 8) areadapted to be inserted. Each terminal 16 is crimped onto a conductor 10,by means of a pair of crimped connections 26, 28, the terminal beingsecured to the strands of the Wire by crimp 26 and to the insulatingsheath on the wire by means of crimp 28. The fork-type terminalscomprise an elongated fiat tab 18 having a slot 20 extending axiallyinwardly from its end to define a pair of parallel tines 22. The innerportion of slot 20 is relatively narrow as shown at 46, the width of theslot being only slightly greater than the width of the post in thisnarrow portion. Inwardly directed contacts 24 are provided on theopposed edges of tines 22 adjacent the ends thereof and they are spacedrelatively close together so that a high pressure electrical contactwill be established between the contact terminals and the post when theterminals are moved into straddling relationship and spread by the postsin the manner described below. As can be discerned, tab 18 is olisetwith respect to connections 26, 28 by transition section 19.

Insulating housing 14 has legs or supports 29 extending from itsunderside so that it can be moved telescopically onto a single terminalpost and will be supported above the surface of board 4 at a positionsuch that it will not interfere with, or otherwise affect, clip-typeconnection 6 which is provided adjacent to the base of the post. Housing14 has an opening 30, 32, 34 extending centrally therethrough which isadapted to receive the upper portion of a terminal post 2 and a pair ofcontact terminals 16. Portion 30 of the opening which is adjacent to thelower end of the housing constitutes an entrance section and has across-sectional configuration closely conforming to and providing asliding frictional fit with the cross-section of post 2 so that thehousing will be stabilized against rotation on the post when the partsare in their assembled relationship. Contact-receiving portion 32 of theopening which is directly above entrance portion 30 has an hourglassconfiguration (see FIGURE 3) having a centrally constricted section 38and a pair of laterally extending cavities 36. The Width of theconstricted section (i.e., the distance between sides 39, 39) issubstantially equal to the corresponding width of post 2 so that theopposed surfaces of this portion of the opening may bear againstopposite sides of the post while the remaining sides will face outwardlyand into cavities 36. The length of the constricted section in the planeat the forked connectors is materially less than the thickness of thepost so that the contacts will bear on the post, as shown in FIGURES 3and 6, and not on the cavity walls. The width of each cavity issubstantially equal to and slightly greater than twice the thickness offorked portion 18 of an individual terminal so that two terminals inback-to-back relationship can be accommodated in the cavities as shownin FIGURES 5 and 6. The cross-sectional length of the cavities, normalto the width, is substantially equal to, and slightly greater than theoverall width of tines 22 when they are spread apart by the post.

A pair of V-shaped ribs 48 are provided on opposite sides ofconductor-receiving portion 4 and contact-receiving portion 32 of theopening in the housing. These ribs extend centrally downwardly in theopening and conform to chamfers 50 on the lower edges of tines 22 ofterminals 16 and function to polarize and locate the terminals in aproper and sequential manner during insertion in a manner describedbelow.

Upper portion 34 of the opening has a cross-section sufiiciently largeto admit a pair of terminals disposed with their fork portions inback-to-back relationship and with their crimped portions 26, 28disposed in parallel relationship with each other. In this respect, itwill be noted that upper section 42 of the cavity of the upper end ofthe housing is slightly enlarged in order to admit insulation crimps 28of the terminals. The transition portion between contact-receivingportion 32 of the opening and conductor-receiving portion 34 comprisesinclined surfaces 40 which slope from opposite sides of the housingdownwardly towards cavities 36 for the purpose of guiding the ends oftines 22 of the contacts into the cavities and into straddlingrelationship with the exposed sides of the post as explained below.

The inner ends of surfaces 40, which form the sides of cavities 36, areslightly smaller in length than the sides of these cavities andconstricted sections 38, as illustrated in FIGURE 4, and this occurs atthe transition between the tab and wire barrel to frictionally retainthe terminals in the housing without restricting action of the tines.

In normal point-to-point connection use, housing 14 is first mounted ona post 2 to which it is desired to connect external conductors 10, 12. Aterminal 16 is then positioned above a desired cavity 42, as shown inFIG- URE 2, in alignment with the post and with its tine portions ingeneral alignment with cavities 36. The terminal is then pusheddownwardly against guide surfaces 40 which guide its forked ends towardthe post and cavities 36, in engagement with sections 38 and intostraddling relationship to the post. If required, a second terminal inlike manner, may then be positioned in or removed from cavity 42. In thefinished connection, the terminals will be in back-to-back relationshipwith their crimp portions 26, 28 facing in opposite directions. It isnot essential that the precise sequence described above be followed; forexample, the terminals can be inserted into the housing together,back-to-back, when complete wiring harnesses are made up and it isconvenient to do so. Many times, however, only a single connector willbe required in a housing.

In the case of the particular embodiment of the invention, the terminalscan be inserted into the housing only in the intended manner. That is tosay, inclined surfaces 40 will function to guide the ends of tines 20towards the post if the terminal is reasonably aligned with cavities 36,as above. Ribs 48 in cooperation with chamfered edges 50 insure that theconductor-retaining crimps 26 and 28 will be properly positioned intheir respective cavities so that either terminal can be connected ordisconnected independent of the other. In other words, with reasonableinitial alignment, it is difficult to insert the terminals in anyorientation other than that shown in FIGURES 5 and 6. Sections 38 servea dual function, as self-centering means to enable the forked ends to beproperly centered with respect to post 2 and as bearing areas forbearing against post 2.

Although terminal post 2 has a small cross-section relative to the sizeof housing 14 and the size of forktype terminals 16, the housing isstabilized against unintentional movement in all directions by themanner in which the housing, cooperating with a terminal or terminals,is fitted onto the post. As previously noted, the housing is stabilizedagainst rotation on the post by constricted entrance portion 30 of theopening since this entrance portion conforms to the cross-section of thepost and has a close fit therewith. The housing is stabilized againstrocking motion in the plane XX of FIGURE 6 by surfaces 39 of theterminal-receiving portions of the opening in the housing. Thesesurfaces 39 extend along and bear against the post for a substantialportion of its length, as best shown in FIGURE 5, so that rocking of thehousing to the left or right in FIGURE 5 is elfectively prevented.Finally, rocking of the housing in the plane YY of FIGURE 6 is preventedby the relationship of fork-type terminals 16 to post 2 and theirrelationship to housing 14. The stability of the housing in the YY planeof FIGURE 6 depends upon the close fit of the terminals in cavities 36and the fact that the upper end of the post extends into narrow sections46 of the slots in the terminals. By virtue of the close fit of theterminals in cavities 36, the terminals are permitted only very limitedmovement within the cavity as is best shown in FIGURE 6. By virtue ofthe fact that the post extends into narrow portions 46 of slots 20 ofthe terminals, very little relative movement of the terminals withrespect to the post is permitted.

The stability if the housing in the YY plane can also be explained byassuming that a force will be applied to the housing from the right orleft in FIGURE 7. Such a force would ordinarily tend to rock the housingin the plane of the drawing of FIGURE 7. However, such a force whenapplied to the housing would actually cause only very limited rockingmotion for the reason that this force would be transmitted to terminals16 (by virtue of the close fit of these terminals in cavities 36) andthence to post 2 by virtue of the relatively close fit of the post inupper narrow portion 46 of slot 20. It should be noted that tines 20 ofthe terminals are highly resistant to flexure in their own planes in theload-bearing areas (within slot portion 46) because of the fact that theforce is transmitted at the relative rigid upper ends of the tines nearthe upper end of slot 20. This fact is of importance in maintaining theelectrical contact between contacts 24 of the terminal and the sides ofthe post when a force is applied to the housing from one side thereof,as viewed in FIGURE 7.

FIGURE 8 shows an alternative embodiment of the invention comprising ahousing 14' having a pair of openings extending therethrough which isadapted to be mounted on a pair of adjacent terminal posts of thepanelboard. The openings in the housing of FIGURE 8 may be in allrespects similar to the opening in housing 14 and the relationship ofthe housing to the posts and the relationship of the terminals to thehousing and post would be as described above. One advantage of the typeof housing shown in FIGURE 8 is that in the event of the application ofa torque to the housing, the two posts extending into the housing wouldprovide added stability and prevent twisting of the housing with respectto the board. Obviously, a housing in accordance with the inventioncould be made with many desired numbers of post-receiving openingstherein.

It will, therefore, be appreciated that the aforementioned and otherdesirable objects have been achieved; however, it should be emphasizedthat the particular embodiments of the invention, which are shown anddescribed herein, are intended as merely illustrative and not asrestrictive of the invention.

What is claimed is:

1. An electrical connector for connecting an electrical conductor to aterminal post comprising an electrical terminal and a dielectrichousing, said terminal having a section electrically connected to saidconductor and a forkedcontact section, said dielectric housing having apassageway extending therethrough, said passageway at one end having aconfiguration conforming substantially to the configuration of said postand into which said post is to be disposed, said passageway having aterminal-receiving area into which said post and said terminal extend,said terminal-receiving area having parallel planes spaced apart adistance sufficient to permit receipt of said terminal therebetween andbearing surface means which constrain said post to remain at leastpartially between said planes substantially centered relative to saidforked-contact section to define centering means to center ends of saidforked-contact section with respect to said post, surface portions insaid housing retaining said terminal after insertion in saidterminal-receiving area.

2. A disengageable electrical connector for connecting conductive meansto a terminal post extending outwardly from a mounting member, saidelectrical connector comprising an electrical terminal and a dielectrichousing, said terminal having a section electrically connected to saidconductive means and a forked-contact section, said dielectric housinghaving an opening extending therethrough, said opening provided with apost entrance, a terminal-receiving section and a terminal entrance,said post entrance conforming to the cross-sectional configuration ofsaid post for snug engagement therewith, said terminal-receiving sectionhaving cavity means extending outwardly from opposite sides of said postentrance, said cavity means including surfaces spaced apart a sufiicientdistance to permit receipt of said forked-contact section therebetween,and bearing surface means extending along opposite surfaces of saidterminal-receiving section for hearing against opposite sides of thepart of said post that extends into said terminal-receiving section andfor cen tering contact ends of said forked-contact section with respectto said post so that said contact ends engage other opposite sides ofsaid post.

3. A connector according to 2 wherein said housing includes a pair ofparallel passageways with at least one terminal in each for cooperationwith a pair of adjacent contact elements on a panelboard.

4. A connector according to 2 wherein said housing includes a pair ofsubstantially identical parallel passageways with at least one terminalin each for cooperation with a pair of adjacent contact elements on apanelboard.

5. An electrical connector for connecting conductor means to a terminalpost extending outwardly from a mounting member, said electricalconnector comprising an electrical terminal and a dielectric housing,said electrical terminal having a section electrically connected to saidconductor means and a forked-contact section, said housing having anopening extending therethrough, said opening having an entrance intowhich said post extends, said entrance conforming substantially to theconfiguration of said post for snug engagement therewith, said openinghaving a terminal-receiving section defining cavities extending parallelto an insertion axis of said opening, bearing-surface means along opposed sides of said terminal-receiving section for bearing engagementwith opposite sides of the part of said post that extends into saidterminal-receiving section, each of said cavities having rib meanscentrally located along a surface spaced outermost from said axis, saidrib means and said opposed sides defining dual terminal-receiving areasin which the forked-contact sections of two electrical terminals aredisposed in electrical engagement with other opposite sides of saidpost, said bearing-surface means providing centering means for centeringcontact ends of the forked-contact sections with respect to the post.

6. An electrical connector for connecting electrical conductors to thecontact elements of a coordinate grid systerm which includes terminalposts mounted in rows on a panelboard, said connector comprising adielectric housing having a pair of passageways extending therethrough,and a pair of electrical terminals respectively disposed in saidpassageways to engage a pair of adjacent contact elements of the gridsystem with the housing arranged to fit over the contact elements inspaced relation to the adjacent elements of the grid, one of saidterminals having a section for electrical connection to a conductor anda forked-contact section, the passageway receiving said termnal at oneend having a construction snugly to receive a terminal post, saidpassageway having a terminalreceiving area into which said post andterminal extend and an enlarged terminal entrance area at the other endto receive the conductor connecting section, said terminal receivingarea having parallel planes spaced apart a distance sufficient to permitreceipt of said terminal therebetween and constraining surface meanswhich constrain said post to remain at least partially between saidplanes substantially centered relative to said forked-contact section todefine centering means to center ends of said forked-contact sectionwith respect to said post, and surface portions in said housingretaining said terminal in said terminal-receiving area.

References Cited UNITED STATES PATENTS 3,325,770 6/1967 'Hammell et al.339-l76 MARVIN A. CHAMPION, Primary Examiner

